Device and method for tacking plaque to blood vessel wall

ABSTRACT

An intravascular device for treating atherosclerotic occlusive disease can include an annular band defining a longitudinal axis between proximal and distal ends. The annular band can have a plurality of barbs on its outer periphery. One or more intravascular devices may be applied in positions along a plaque accumulation site as needed to stabilize the site and/or hold pieces of plaque out of the way of blood flow. The barbs may be pressed into the plaque and/or blood vessel walls.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.11/955,331 filed Dec. 12, 2007, now U.S. Pat. No. 7,896,911, which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

This invention relates to treatment of atherosclerotic occlusive diseaseby intravascular procedures for pushing and holding plaque accumulatedon the blood vessel walls out of the way for reopened blood flow.

BACKGROUND OF INVENTION

Atherosclerotic occlusive disease is the primary cause of stroke, heartattack, limb loss, and death in the US and the industrialized world.Atherosclerotic plaque forms a hard layer along the wall of an arteryand is comprised of calcium, cholesterol, compacted thrombus andcellular debris. As the atherosclerotic disease progresses, the bloodsupply intended to pass through a specific blood vessel is diminished oreven prevented by the occlusive process. One of the most widely utilizedmethods of treating clinically significant atherosclerotic plaque isballoon angioplasty.

Balloon angioplasty is an accepted method of opening blocked or narrowedblood vessels in every vascular bed in the body. Balloon angioplasty isperformed with a balloon angioplasty catheter. The balloon angioplastycatheter consists of a cigar shaped, cylindrical balloon attached to acatheter. The balloon angioplasty catheter is placed into the arteryfrom a remote access site that is created either percutaneously orthrough open exposure of the artery. The catheter is passed along theinside of the blood vessel over a wire that guides the way of thecatheter. The portion of the catheter with the balloon attached isplaced at the location of the atherosclerotic plaque that requirestreatment. The balloon is inflated to a size that is consistent with theoriginal diameter of the artery prior to developing occlusive disease.When the balloon is inflated, the plaque is broken. Cleavage planes formwithin the plaque, permitting the plaque to expand in diameter with theexpanding balloon. Frequently, a segment of the plaque is more resistantto dilatation than the remainder of the plaque. When this occurs,greater pressure pumped into the balloon results in full dilatation ofthe balloon to its intended size. The balloon is deflated and removedand the artery segment is reexamined. The process of balloon angioplastyis one of uncontrolled plaque disruption. The lumen of the blood vesselat the site of treatment is usually somewhat larger, but not always andnot reliably.

Some of the cleavage planes created by fracture of the plaque withballoon angioplasty form dissection. A dissection occurs when a portionof the plaque is lifted away from the artery and is not fully adherentand may be mobile or loose. The plaque that has been disrupted bydissection protrudes into the flowstream. If the plaque lifts completelyin the direction of blood flow, it may impede flow or cause acuteocclusion of the blood vessel. There is evidence that dissection afterballoon angioplasty must be treated to prevent occlusion and to resolveresidual stenosis. There is also evidence that in some circumstances, itis better to place a metal retaining structure, such as stent to holdopen the artery after angioplasty and force the dissected material backagainst the wall of the blood vessel to create an adequate lumen forblood flow.

Therefore, the clinical management of dissection after balloonangioplasty is currently performed primarily with stents. As illustratedin FIG. 24A, a stent is a tube having a diameter that is sized to theartery. A stent is placed into the artery at the location of adissection to force the dissection flap against the inner wall of theblood vessel. Stents are usually made of metal alloys. They have varyingdegrees of flexibility, visibility, and different placement techniques.Stents are placed in every vascular bed in the body. The development ofstents has significantly changed the approach to minimally invasivetreatment of vascular disease, making it safer and in many cases moredurable. The incidence of acute occlusion after balloon angioplasty hasdecreased significantly with stents.

However, stents have significant disadvantages and much research anddevelopment is being done to address these issues. Stents induce repeatnarrowing of the treated blood vessel (recurrent stenosis). Recurrentstenosis is the “Achilles heel” of stenting. Depending on the locationand the size of the artery, in-growth of intimal hyperplastic tissuefrom the vessel wall directly through the tines or openings in the stentmay occur and cause failure of the vascular reconstruction by narrowingor occlusion of the stent. This may occur any time after stentplacement. In many cases, the stent itself seems to incite local vesselwall reaction that causes stenosis, even in the segment of the stentthat was placed over artery segments that were not particularly narrowedor diseased during the original stent procedure. This reaction of theblood vessel to the presence of the stent is likely due to thescaffolding effect of the stent. This reaction of recurrent stenosis ortissue in growth of the blood vessel is in response to the stent. Thisactivity shows that the extensive use of metal and vessel coverage inthe artery as happens with stenting is contributing to the narrowing.The recurrent stenosis is a problem because it causes failure of thestent and there is no effective treatment. Existing treatment methodsthat have been used for this problem include; repeat angioplasty,cutting balloon angioplasty, cryoplasty, atherectomy, and even repeatstenting. None of these methods have a high degree of long-term success.

Stents may also fracture due to material stress. Stent fracture mayoccur with chronic material stress and is associated with thedevelopment of recurrent stenosis at the site of stent fracture. This isa relatively new finding and it may require specialized stent designsfor each application in each vascular bed. Structural integrity ofstents remains a current issue for their use. Arteries that areparticularly mobile, such as the lower extremity arteries and thecarotid arteries, are of particular concern. The integrity of the entirestent is tested any time the vessel bends or is compressed anywherealong the stented segment. One reason why stent fractures may occur isbecause a longer segment of the artery has been treated than isnecessary. The scaffolding effect of the stent affects the overallmechanical behavior of the artery, making the artery less flexible.Available stenting materials have limited bending cycles and are proneto failure at repeated high frequency bending sites.

Many artery segments are stented even when they do not require it,thereby exacerbating the disadvantages of stents. There are severalreasons for this. Many cases require more than one stent to be placedand often several are needed. Much of the stent length is often placedover artery segments that do not need stenting and are merely adjoiningan area of dissection or disease. Stents that are adjusted to theprecise length of the lesion are not available. When one attempts toplace multiple stents and in the segments most in need of stenting, thecost is prohibitive since installation and material is required perstent. The time it takes to do this also adds to the cost and risk ofthe procedure. The more length of artery that receives a stent that itdoes not need, the more stiffness is conferred to the artery, and themore scaffolding affect occurs. This may also help to incite thearterial reaction to the stent that causes recurrent stenosis.

SUMMARY OF INVENTION

In accordance with the present invention, a device (and related methodof deployment) for treating atherosclerotic occlusive disease comprisesa thin, annular band of durable, flexible material (a “plaque tack”)having a plurality of barbs or anchoring elements on its outer annularperiphery, which is installed intravascularly in one or more specificpositions of a plaque accumulation site. The plaque tack is dimensionedand designed to be applied with a spring force against the plaque topress and hold it against the blood vessel walls. The barbs or anchoringelements are embedded into or at least emplaced in physical contactagainst the plaque by the spring force so that the plaque tack isretained securely in position from being dislodged. The plaque tack isgenerally used after a balloon angioplasty procedure to reopen thevessel lumen for desired blood flow. The annular band of the plaque tackhas a width in the axial direction of the vessel walls that is less thanits diameter, in order to minimize the emplacement of foreignscaffolding structure in the blood vessel. One or more tacks are appliedonly in positions along the length of a plaque accumulation site wherespecific holding forces are needed to stabilize the site and/or holdpieces of plaque out of the way of blood flow. The barbs or anchorpoints of the tack(s) may be pressed with an expansion force into theplaque and/or vessel walls by a post-installation balloon expansionprocedure.

In the present invention, the plaque tack device is designed as aminimally invasive approach to tacking loose or dissectedatherosclerotic plaque to the wall of the artery, as illustrated in FIG.24B. It may be used to treat either de novo atherosclerotic lesions orthe inadequate results of balloon angioplasty. It is designed tomaintain adequate lumen in a treated artery without the inherentdisadvantages of vascular stents. The device may also be used toadminister medications, fluid, or other treatment (“eluting”) agentsinto the atherosclerotic plaque or the wall of the blood vessel or intothe bloodstream.

The plaque tack and installation procedure may be designed in a numberof ways that share a common methodology of utilizing the spring force ofa spring-like annular band to enable the tack to be compressed, folded,or plied to take up a small-diameter volume so that it can be moved intoposition in the blood vessel on a sheath or catheter, then released,unfolded or unplied to expand to its full diametral size within theblood vessel walls.

In a first embodiment, the plaque tack is formed as a thin, elasticallypliable ribbon having a row of pointed cutouts formed on an outward sidealong its longitudinal length. It can be made of a corrosion-resistantmetal or durable polymer. A preferred material is a metal having“shape-memory” (such as Nitinol) which allows it to be formed initiallywith an annular shape prior to forming in a linear shape, then resumeits annular shape when exposed for a length of time at internal bodytemperature. The ribbon tack can be delivered in linear form carried ona delivery head of a catheter or sheath to the desired position in theblood vessel and pushed along a curved tunnel into its annular shape atthe plaque site. The ribbon tack in its annular shape presses againstthe plaque with a spring force, and remains in the annular shape due toits shape-memory at internal body temperature. When deployed in itsannular shape, the row of tongues of cutout points are opened andexposed to point outwardly from the now curved surface of the annularband, so that they can be embedded into or at least emplacedfrictionally against the plaque to prevent the tack from becomingdislodged.

In a second embodiment, the plaque tack is formed as a folding ring tackhaving V-shaped segments for folding and inverted-V-shaped points. TheV-shaped segments allow the ring to be radially compressed to asmall-diameter volume for carriage in a deployment tube on the end ofthe sheath. At the desired position, the compressed ring tack isreleased from the deployment tube so that the ring springs out to itsfull diametral shape and the outward points act as barb or anchor pointsembedded into or pressed against the plaque.

In a third embodiment, the plaque tack is formed as a flexible ring ofpliable material having an array of outer barbs on an outward side ofthe ring, and an array of inner radial fingers, wherein the array offingers are used to displace the outer barbs to lie horizontally flat inone axial direction when the fingers are pushed in the opposite axialdirection. With the outer barbs displaced to lie horizontally flat, theflexible ring can be loaded on the outer surface of a catheter deliverytube and held down by a retainer element to allow insertion into theblood vessel. The fingers are removed so that they are not present toobscure the blood vessel when the tack is installed. At the desiredposition, the retainer element is displaced to release the flexible ringtack to spring up with its barbs extending radially outwardly forembedding into the plaque.

In a fourth embodiment, the plaque tack is formed as a annular band in acoil shape with opposite ends unjoined. The ends are pulled in oppositedirections to flatten the coil tack in a tight spiral to reduce itscross-section to a smaller-diameter volume for loading on a catheterdelivery tube while being held down by a shell or cover for insertion inthe blood vessel. At the desired position in the blood vessel, the coveris displaced to release the tack and allow it to expand back to its fullannular shape in position against the plaque.

In a fifth embodiment, the plaque tack is formed as a compressible wiremesh tack with barbs formed on its outer surface. The wire mesh tack canbe compressed to reduce its cross-section to a smaller-diameter volumeso that it can be loaded on a catheter delivery tube held down by acover or shell for insertion in the blood vessel. At the desiredposition in the blood vessel, the shell is displaced to release the tackand allow it to expand back to its full annular shape in positionagainst the plaque.

In some embodiments, an intravascular device can comprise an annularband defining a longitudinal axis between proximal and distal ends ofthe device. The annular band can include a first plurality of wingsalong a first side of the annular band, a second plurality of wingsalong a second side of the annular band, and a plurality of barbspositioned on the annular band between the first plurality of wings andthe second plurality of wings. The first side of the annular band can bespaced from the second side along the longitudinal axis.

Certain embodiments of the first plurality of wings can have each wingof the first plurality of wings having first and second struts forming aproximal apex and extending longitudinally such that the proximal apexesof the first plurality of wings form the proximal most end of thedevice. In addition, certain embodiments of the second plurality ofwings can have, each wing of the second plurality of wings having thirdand fourth struts forming a distal apex and extending longitudinallysuch that the distal apexes of the second plurality of wings form thedistal most end of the device.

The plaque tack solves the problems associated with stents by beingplaced only in areas of plaque that require a holding force. Its minimalaxial length enables less scaffolding structure to be used in the arterythan with typical stents, and thereby may incite less body reaction andless recurrent stenosis. Only segments of the artery that need treatmentare covered and healthy arteries are not treated. The tack is designedfor tacking or embedding into the artery wall which is more advantageousthan requiring deployment of a “sleeve” type of length associated withstenting. A small amount of foreign body contact with the blood streamand the wall of the artery will incite less reaction. The tack occupiesonly a narrow section of the artery, thereby limiting bending stresseson the tack as seen in the failure modes of stents. The plaque tackcovers a very short distance and does not affect the overall mechanicalproperties of an entire segment of artery. The material stress will bemuch less than that on a stent that has to scaffold the entire arterysegment. The simplicity of the plaque tack design allows it to be madeat lower material and fabrication cost, and to avoid excessive joints orwelded points of the type that can weaken a stent structure.

Other objects, features, and advantages of the present invention will beexplained in the following detailed description of the invention havingreference to the appended drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are schematic diagrams of a first embodiment in ribbonform for the plaque tack device of the present invention.

FIG. 2 is a side view of the first embodiment of the ribbon tack of FIG.1B in its annular shape after deployment.

FIG. 3 is a plan view of the ribbon tack of FIG. 1B in its annular shapeafter deployment.

FIGS. 4A and 4B are alternative versions of the ribbon tack of FIGS. 1Band 1A respectively, having stabilizing wings.

FIG. 5 is a schematic diagram of a third embodiment of flexing star tackhaving outward triangular anchor points and inward radial fingers.

FIG. 6 is a schematic diagram of a fourth embodiment of a spiral coiltack with unjoined ends that can be pulled in opposite directionshorizontally to reduce its cross-sectional diameter for insertion in theblood vessel.

FIGS. 7A-7D show alternative shapes for the flexing star tack of FIG. 5with a variety of different anchor point designs.

FIG. 8 is a photo image of the ribbon tack of FIG. 1B showing thetongues or cutout portions protruding at an angle from the metal stripwhen the tack is bent into an annular shape.

FIG. 9 is a close-up image of the anchor points of the ribbon tack ofFIG. 1B.

FIG. 10 is a photo image of the ribbon tack of FIG. 1B prior toinstallation.

FIG. 11 illustrates a pattern of capillaries formed on the tongues ofthe ribbon tack of FIG. 1B for delivering plaque-growth retardingmaterial into the plaque.

FIG. 12 is a close-up view of the capillaries formed on the tongues ofthe ribbon tack in FIG. 11.

FIG. 13 is a schematic diagram of a second embodiment of a folding ringtack having inner V-shaped segments for folding and outerinverted-V-shaped points for anchoring.

FIG. 14 is a schematic representation of the ribbon tack loaded inmultiple units on the delivery head of a catheter tube for insertioninto the blood vessel.

FIG. 15 is a detailed view of the delivery head for the ribbon tacks inFIG. 14.

FIG. 16 is a schematic representation of the folding ring tack loaded inmultiple units on the delivery head of a catheter tube with a retainerfor holding them on the sheath in compressed form.

FIG. 17 is a schematic representation showing the folding ring tackpartially deployed.

FIG. 18 is a schematic representation showing folding ring tack fullydeployed in the blood vessel.

FIG. 19A shows a fifth embodiment of a wire mesh tack in end view, FIG.19B shows it in side view, FIG. 19C shows the wire mesh tack inperspective, and FIG. 19D shows a section of the wire mesh tack in adetailed view.

FIG. 20 is a schematic representation showing multiple units of the wiremesh tack loaded on a catheter delivery tube.

FIG. 21 is a schematic representation showing the wire mesh tackreleased from the delivery head and fully expanded in the blood vessel.

FIG. 22 is a schematic representation the spiral coil tack loaded inmultiple units on the delivery head of a sheath and held down by aretainer cover.

FIG. 23 is a schematic representation showing the spiral coil tackreleased from the delivery head and fully expanded in the blood vessel.

FIG. 24A illustrates the use of a stent installed after angioplasty asconventionally practiced in the prior art.

FIG. 24B illustrates the use of the plaque tack installed afterangioplasty demonstrating its advantages over the prior art.

DETAILED DESCRIPTION OF INVENTION

In the following detailed description of the invention, certainpreferred embodiments are illustrated providing certain specific detailsof their implementation. However, it will be recognized by one skilledin the art that many other variations and modifications may be madegiven the disclosed principles of the invention. Reference for thedescription is made to the accompanying drawings, wherein like referencenumerals refer to similar parts throughout the several views.

As illustrated in FIG. 24B, the plaque tack device in the presentinvention generally comprises a thin, annular band of durable, flexiblematerial having a plurality of barbs or anchoring elements on its outerannular periphery. The plaque tack is dimensioned diametrally and isdesigned to be applied with a spring force against the plaque to pressand hold it against the blood vessel walls. The barbs or anchoringelements are embedded into or at least emplaced in physical contactagainst the plaque by the spring force of the plaque tack. The plaquetack extends over only a small area in the axial direction of the vesselwalls, in order to minimize the amount of foreign structure placed inthe blood vessel. One or more tacks are applied only in positions alongthe length of a plaque accumulation site where specific holding forcesare needed to stabilize the site and/or hold pieces of plaque out of theway of blood flow.

The plaque tack and installation procedure may be designed in a numberof ways that share a common methodology of utilizing the spring force ofa spring-like annular band to enable the tack to be compressed, folded,or plied to take up a small-diameter volume so that it can be moved intoposition in the blood vessel on a sheath or catheter, then released,unfolded or unplied to expand to its full-diametral size within theblood vessel walls.

In the following description, five general embodiments of the plaquetack device and how to deliver it are explained in detail, referred toas: (1) ribbon tack; (2) folding ring tack; (3) flexible ring tack; (4)spiral coil tack; and (5) wire mesh tack. All these embodiments aredelivered into the blood vessel from endovascular insertion. Thedelivery device for each involves a delivery apparatus that has somefeatures of a vascular sheath. The delivery device for each is differentand has features that are specifically designed to deliver the specifictack

Referring to FIGS. 1A and 1B, a first preferred embodiment of the plaquetack device is shown in two versions of a ribbon tack, each having alinear, flat shape like a ribbon. The version in FIG. 1A has a base end31, rows 33 of cutout tongues or apertured portions that open out aspointed barbs or anchors, and a retainer end 35. The version in FIG. 1Bhas a base end 32, single row 34 of cutout portions that open out aspointed barbs or anchors, and a retainer end 35. Each version may bemade of a material such as a corrosion-resistant metal, polymer,composite or other durable, flexible material. A preferred material is ametal having “shape-memory” (such as Nitinol) which allows it to beformed initially with an annular shape prior to forming in a linearshape, then resume the annular shape when exposed for a length of timeat internal body temperature. When the strip is deployed in the bloodvessel, it is curved into an annular shape. FIG. 2 shows the view of thestrip of material in FIG. 1B after it is curved into its preferred shapeof deployment in the blood vessel, leaving a large inner, open area 36for blood flow through it. The barbs are shown opened to outwardlypointing angles 37 due to bending forces so that they point toward thewall or surface of the blood vessel.

In a typical configuration, the ribbon tack may have a width of about0.1 to 5 mm, a diameter (when curved in annular shape) of about 3-10 mm,a length (when extended linearly) of about 10 to 30 mm, and a barbheight from 0.2 to 5 mm. In general, the annular band of the plaque tackhas a width in the axial direction of the vessel walls that is less thanits diameter, in order to minimize the amount of foreign structure to beemplaced in the blood vessel. For larger vessels and tack designs madeof wire, the width/diameter ratio can be as low as 1/10 to 1/100.

FIG. 3 is a schematic diagram showing a top view of the ribbon tack bentinto its annular shape. FIGS. 4A and 4B show alternative versions of theribbon tack having stabilizing wings provided along its side edges foradded lateral stability when deployed in the blood vessel. The versionin FIG. 4A has a single row of cutout portions that open out as pointedbarbs or anchors. The version in FIG. 4B has rows of cutout tongues orapertured portions that open out as pointed barbs or anchors. Eachversion may be made of a material such as a corrosion-resistant metal,polymer, composite or other durable, flexible material. A preferredmaterial is a metal having “shape-memory” (such as Nitinol). When thestrip is deployed in the blood vessel, it can be in an annular shape andthe barbs can point outwardly so that they point toward the wall orsurface of the blood vessel. FIG. 8 shows an overhead photo image of theribbon tack with anchors protruding at an outward angle. FIG. 9 is aclose-up image of the anchors of the annular strip. FIG. 10 is anoverhead image of the metal strip extended linearly when at rest.

FIG. 11 illustrates a pattern of capillaries 25 that may be formed byetching the surfaces of the tongues or cutout portions for deliveringplaque-growth retarding material or other treatment agent where the tackis installed at the plaque accumulation site. FIG. 12 illustrates howthe pattern of capillaries 25 is supplied with plaque-retarding ortreatment material through a supply conduit 24. The material may beeither resident within the channels prior to insertion of the tack ortransferred from a reservoir on the inside of the annulus, through ahole to the outside of the component on the surface, into the anchoredobject, and into the tissue wall, enabling delivery of a treatment orsuch that enables additional preventative measures for retaining optimalblood flow. The forces that enable the transfer of the material from theinside of the annulus through the tree branches might be eithercapillary force or a combination of capillary and hydraulic pressure.Capillary action, capillarity, capillary motion, or wicking is theability of a substance to draw another substance into it. The standardreference is to a tube in plants but can be seen readily with porouspaper. It occurs when the adhesive intermolecular forces between theliquid and a substance are stronger than the cohesive intermolecularforces inside the liquid. The effect causes a concave meniscus to formwhere the substance is touching a vertical surface.

The array of barbs or anchor points is used for linking the annular bandof the tack with the plaque mass or blood vessel wall. The barb is madeof a sufficiently rigid material to sustain a locking relationship withthe blood vessel tissue and/or to pierce the plaque and maintain alocking relationship therewith. The barb is comprised of a head disposedon a support body. Preferably, the head and support body are integralwith each other and are constructed as a single piece. The barb mayproject at an angle of 90 degrees to the tangent of the annular band, oran acute angle may also be used.

Referring to FIG. 13, a second preferred embodiment of the plaque tackdevice is formed as a folding ring tack having inner V-shaped segmentsfor folding alternating with outer inverted-V-shaped points. TheV-shaped segments allow the ring to be radially folded to asmall-diameter volume for carriage on a deployment tube on the end ofthe sheath. At the desired position in the blood vessel, the compressedring tack is released from the deployment tube so that the ring springsout to its full diametral shape and the outward points act as barb oranchor points embedded into or pressed against the plaque. The foldingring tack is preferably made of metal wire material. Other options forthe shape of the anchors on the outer surface may be used.

Referring to FIG. 5, a third preferred embodiment of the plaque tackdevice is formed as a flexible ring tack having a pliable or hingedstructure and formed with an array of radially extending points 59 on anouter side of the ring, and an array of inner radial fingers 50. Thearray of inner radial fingers are used to displace the points to liehorizontally flat in one axial direction when the fingers and pushed inthe opposite axial direction. With the barbs or points displaced to liehorizontally flat, the flexible ring tack can be loaded on a catheterdelivery tube and held down in by a cover. The fingers are then removedso that they are not present to obscure the blood vessel when the tackis installed. At the desired position, the retainer cover is displacedto release the ring tack which springs up to extend its points radiallyoutwardly for embedding into the plaque. The body of the annular ringmay have differing degrees of thickness and different designs for thefingers in the central area, such as the raised triangular anchors 59and radial fingers 50 shown in FIG. 5.

FIGS. 7A-7D show alternative shapes for the third embodiment of FIG. 5with a variety of different anchoring designs 72, 73, 78, 80. Thefingers 76, 77 for bending the points flat for insertion are includedwith any of the designs. When the fingers are removed after pre-loading,and the flexible ring tack has been deployed, the inner area 74, 75within the annular ring 79, 82 is left unobstructed.

Referring to FIG. 6, a fourth preferred embodiment of the plaque tackdevice is formed in a coil shape 64 with ends unjoined and with barbs orpoints 61 on its outer periphery. The ends are pulled longitudinally inopposite directions to flatten the annular band to a spiral shapeextending linearly so that it can be carried around or inside the lengthof a tubular sheath into the blood vessel held in place by a retainerelement. At the desired position in the blood vessel, the retainerelement is released to allow the tack to expand back to itsfull-diameter annular shape against the plaque.

FIGS. 14 and 15 show a preferred delivery method for the ribbon tackdescribed above. Multiple flat ribbon strips 80 in linear form arearranged in parallel in an array 80 a carried on the outer surface ofthe delivery head 81 of a tubular catheter 82. Each ribbon strip 80 iscarried in a respective barrel 83 of a multi-barreled tack magazine 84which wraps around the catheter, as indicated in FIG. 14. The catheterhas an internal pressure chamber 85 which is loaded with saline solutionor CO2 gas used to eject a ribbon strip from its barrel as it is movedby rotation of the magazine 84 in the direction RR to bring each ribbonstrip in turn to an ejector position (left side of the figure) inalignment with an ejector track 86 formed in the delivery head.Pressurized fluid from the pressure chamber 85 is used to push a movermember that ejects the ribbon strip from its barrel into the ejectortrack 86. As shown in more detail in FIG. 15, the ejector track 86 leadsinto a curved outlet tunnel 87 which bends the ribbon strip towards itsannular shape as the delivery head rotates. The outlet tunnel 87 curves90 degrees from the axial direction of the catheter to the radialdirection facing toward the vessel walls. This curved tunnel capturesthe end of the ribbon pushed into the ejector track and causes themiddle part of the ribbon strip to bulge outward toward the blood vesselwall where it will lay down perpendicular to the axis of the bloodvessel. The delivery head of the catheter rotates as part of thedelivery mechanism. As the ribbon is being pushed out of the deliveryhead under hydraulic or propulsive pressure, the rotation of thedelivery head allows the ribbon to be laid down in its annular shapespanning the blood vessel walls.

A preferred delivery method for the second described embodiment of thefolding ring tack of FIG. 13 is shown in FIGS. 16, 17, and 18. Thefolding ring tack has an overall circular shape with inner V bends thatallow it to be folded in zig-zag fashion to a compressed smaller-volumeform for loading onto the delivery end of a catheter tube 92. As shownin FIG. 16, multiple units of the compressed folding ring tacks 90 arearrayed in a series on the surface of the tube. The catheter tube ishollow and lined with a fabric 91 that slides over the outer surface ofthe tube and is pulled over the end of the tube into its interior(direction of the U-shaped arrows). The fabric is made of a strong,durable material with low friction such as Teflon or Kevlar or likematerial. Multiple tacks may be loaded onto the surface of the fabriccovering the outer surface of the catheter tube. The tacks are held downin their compressed, folded form by a shell or cover 93 that istelescoped over the catheter tube and prevents early deployment of thetacks. The shell may be a transparent plastic sleeve or similarstructure having its end set back a small distance from the end of thecatheter tube. As the fabric 91 is pulled inside the tube is pulled, thecompressed tack 90 is advanced toward the end of the catheter tube. Whenthe tack reaches the end, it is released from the shell 93, and springsback to its original shape of an annular band with outer barbs the embedor are emplaced against the plaque and blood vessel walls. FIG. 17 showsthis process in action with the tack half-way deployed. The fabric 91advancing the tack 90 is being pulled into the center of the hollowdelivery tube. FIG. 18 shows the tack in place in the blood vessel afterit has been separated from the delivery catheter.

The third preferred embodiment of the flexing ring tack of FIG. 5 may bedeployed by a similar method as described above, by loading onto asimilar sliding fabric carrier which is pulled over the outer surface ofa catheter tube, with a shell sleeved over the tube for retaining thetacks from deployment until each reaches the end of the tube.

A fifth embodiment of the plaque tack in the form of a wire mesh tack isillustrated in FIGS. 19A-D, and its manner of deployment in FIGS. 20 and21. In FIG. 19A, the wire mesh tack is shown in end view having anannular band 100 a formed of interleaved wire mesh, and outer points orbarbs 100 b. The wire mesh tack is made of thin metal wire which islooped and interleaved in a mesh that is welded, soldered, looped and/orlinked together into the desired mesh shape. FIG. 19B shows the wiremesh tack in side view with barbs projecting from the annular band 100a. The barbs on its outward surface will contact and embed into the wallof the blood vessel. FIG. 19C shows the wire mesh tack at rest in itsfully expanded state in perspective view, and FIG. 19D shows a sectionof the wire mesh tack in a detailed view. The intermeshed pattern formedby the wire mesh is specifically designed so that it can be compressedradially inward to a smaller-volume size for loading on a catheterdelivery device to be inserted into the blood vessel.

A preferred method of delivery for the wire mesh tack is shown in FIG.20. Multiple wire mesh tacks 100 are compressed to its smaller-volumesize and loaded onto the surface of a catheter delivery tube 102 in anarray 100 x over a given length of the tube. As in the previouslydescribed delivery method, a cover or shell 103 is sleeved over thesurface of the tube to hold the tacks in their compressed state andprevent early deployment of the tacks. As the cover 103 is withdrawndown the length of the tube, each wire mesh tack in turn is released andexpands to its full-volume size. FIG. 21 shows the wire mesh tack 100expanded and deployed in the blood vessel.

A preferred delivery method for the fourth described embodiment of thespiral coil tack of FIG. 6 is illustrated in FIGS. 22 and 23. The coilshaped tack in FIG. 6 is formed with barbs and a band with unjoined endsthat may or may not have a taper with a varying degrees of thicknessalong its length. This design is uncoiled in its rest state and lookslike a “broken” circle. The coil tack can be compressed to a fraction ofits at-rest diameter by pulling its ends in opposite linear directionsto form a tight spiral that occupies a smaller-diameter volume so thatit can be inserted into the blood vessel. When released it can expand toseveral times the diameter of its spiral form. FIG. 22 shows multipleunits of spiral coil tacks 110 loaded in the interior of the catheterdelivery tube 112. When the tack is compressed, it occupies severalspiral turns and it spaced out longitudinally. In this case, thedelivery catheter is lined with fabric 113 slidable on its interiorsurface over the end of the tube to its outside (indicated by the pairof U-shaped arrows). As the fabric is pulled through the center of thetube, the tack is advanced toward the end of the delivery catheter. Whenthe tack reaches the end of the delivery catheter, the tack is releasedfrom the tube and re-expands to its full size to be deployed into thewall of the blood vessel. FIG. 23 shows the tack deployed in the bloodvessel.

In the embodiments described above, the preferred plaque tack device maybe made from Nitinol, silicon composite (with or without an inertcoating), polyglycolic acid, or some other superelastic material. Theanchors can have a preferred length of 0.2 mm to 5 mm. The strip ofmaterial can be created from ribbon, round or rectangular wire or asheet of material processed through photolithographic processing, laseror water cutting, chemical etching or mechanical removal of the finalshape, or the use of bottom up fabrication, for instance chemical vapordeposition processes, or the use of injection modeling, hot embossing,or the use of electro or electroless-plating. It may be fabricated frommetal, plastic, ceramic, or composite material.

The plaque tack is designed to be inherently self-aligning, i.e., itsmechanical installation can accommodate small misalignments. This servesto facilitate placing the tacks in specific locations within diseasedblood vessels. With respect to the piercing barb that has a pointedshape, it can be used to embed in objects having irregular surfaces suchas plaque or dissected or damaged artery surfaces. After deployment ofthe plaque tack, the surgeon has the option of placing an angioplastyballoon at the site of the tack and inflating the balloon to press theanchor or anchors into the wall of the blood vessel.

It is to be understood that many modifications and variations may bedevised given the above description of the principles of the invention.It is intended that all such modifications and variations be consideredas within the spirit and scope of this invention, as defined in thefollowing claims.

The invention claimed is:
 1. An intravascular device comprising: anannular band defining a longitudinal axis between proximal and distalends of the device and having: a first plurality of wings along a firstside of the annular band, each wing of the first plurality of wingshaving first and second struts forming a proximal apex and extendinglongitudinally such that the proximal apexes of the first plurality ofwings form the proximal most end of the device; a second plurality ofwings along a second side of the annular band, the first side of theannular band spaced from the second side along the longitudinal axis,each wing of the second plurality of wings having third and fourthstruts forming a distal apex and extending longitudinally such that thedistal apexes of the second plurality of wings form the distal most endof the device; and a plurality of barbs positioned along a circumferenceof the annular band between the first plurality of wings and the secondplurality of wings, wherein each of the barbs of the plurality of barbsextend from the annular band pointed along a single circumferentialdirection; wherein the plurality of barbs comprises a first plurality ofbarbs and the device further comprises a second plurality of barbspositioned along the circumference of the annular band between the firstplurality of wings and the second plurality of wings, wherein each ofthe barbs of the second plurality of barbs extend from the annular bandpointed along the single circumferential direction; and wherein twoadjacent barbs, one from the first plurality of barbs and the other fromthe second plurality of barbs are aligned along the longitudinal axis.2. The device of claim 1, wherein the barbs are configured to extendoutward from the annular band when the device is bent out of an initialat rest condition.
 3. The device of claim 1, wherein the length of eachof the plurality of barbs is greater than the distance between a tip ofthe barb and the annular band.
 4. The device of claim 1, wherein theannular band is made of shape memory material.
 5. The device of claim 1,wherein a dimension of the annular band along the longitudinal axisbetween proximal most and distal most ends is less than a diameter ofthe annular band.
 6. The device of claim 1, wherein one apex of theproximal apexes of the first plurality of wings and one apex of thedistal apexes of the second plurality of wings form a pair of adjacentmost opposing apexes, and wherein these opposing apexes are offset alongthe longitudinal axis.
 7. The device of claim 1, wherein a first apex ofthe proximal apexes of the first plurality of wings and a second apex ofthe distal apexes of the second plurality of wings form a pair ofadjacent most opposing apexes, and wherein at least one barb of theplurality of barbs is positioned between the first apex and the secondapex.
 8. The device of claim 1, wherein a wing of the first plurality ofwings and a wing of the second plurality of wings both are configured toextend parallel with the longitudinal axis when the device is in a fullydeployed condition in situ.
 9. The device of claim 1, wherein the firstand second plurality of wings are configured to extend along thelongitudinal axis to provide stability to the device implanted within ablood vessel.
 10. The device of claim 1, wherein said barbs are formedwith conduits for enabling plaque treatment material to be conducted tothe surface of the barbs through capillary channels.
 11. The device ofclaim 1, wherein the first strut of at least one of the wings of thefirst plurality of wings is directly connected to one of the pluralityof barbs.
 12. The device of claim 1, wherein at least one of the firststrut and the second strut of each wing of the first plurality of wingsor at least one of the third strut and the fourth strut of each wing ofthe second plurality of wings is directly connected to one of theplurality of barbs.
 13. An intravascular device comprising: an annularband defining a longitudinal axis between proximal and distal ends ofthe device and having: a first plurality of wings along a first side ofthe annular band, each wing of the first plurality of wings having firstand second struts forming a proximal apex and extending longitudinallysuch that the proximal apexes of the first plurality of wings form theproximal most end of the device; a second plurality of wings along asecond side of the annular band, the first side of the annular bandspaced from the second side along the longitudinal axis, each wing ofthe second plurality of wings having third and fourth struts forming adistal apex and extending longitudinally such that the distal apexes ofthe second plurality of wings form the distal most end of the device;wherein one apex of the proximal apexes of the first plurality of wingsand one apex of the distal apexes of the second plurality of wings forma pair of adjacent most opposing apexes, and wherein these opposingapexes are offset along the longitudinal axis; and a plurality of barbspositioned along a circumference of the annular band between the firstplurality of wings and the second plurality of wings, wherein each ofthe barbs of the plurality of barbs extend from the annular band pointedalong a single circumferential direction; wherein the first and secondplurality of wings are configured to extend along the longitudinal axisto provide stability to the device when implanted within a blood vessel.14. The device of claim 13, wherein the device is made of shape memorymaterial.
 15. The device of claim 13, wherein a dimension of the devicedefined from the proximal most end to the distal most end along thelongitudinal axis is less than a diameter of the annular band.
 16. Thedevice of claim 13, wherein the plurality of barbs comprises a firstplurality of barbs and the device further comprises a second pluralityof barbs positioned along the circumference of the annular band betweenthe first plurality of wings and the second plurality of wings, whereineach of the barbs of the second plurality of barbs extend from theannular band.
 17. The device of claim 16, wherein two adjacent barbs,one from the first plurality of barbs and the other from the secondplurality of barbs are aligned along the longitudinal axis.
 18. Thedevice of claim 13, wherein said barbs are formed with conduits forenabling plaque treatment material to be conducted to the surface of thebarbs through capillary channels.
 19. The device of claim 13, wherein atleast one of the first strut and the second strut of each wing of thefirst plurality of wings or at least one of the third strut and thefourth strut of each wing of the second plurality of wings is directlyconnected to one of the plurality of barbs.
 20. An intravascular devicecomprising: an annular band defining a longitudinal axis betweenproximal and distal ends of the device and having: a first plurality ofwings along a first side of the annular band, each wing of the firstplurality of wings having first and second struts forming a proximalapex and extending longitudinally such that the proximal apexes of thefirst plurality of wings form the proximal most end of the device; asecond plurality of wings along a second side of the annular band, thefirst side of the annular band spaced from the second side along thelongitudinal axis, each wing of the second plurality of wings havingthird and fourth struts forming a distal apex and extendinglongitudinally such that the distal apexes of the second plurality ofwings form the distal most end of the device; and a plurality of barbspositioned along a circumference of the annular band between the firstplurality of wings and the second plurality of wings, wherein each ofthe barbs of the plurality of barbs extend from the annular band pointedalong a single circumferential direction; wherein the plurality of barbscomprises a first plurality of barbs and the device further comprises asecond plurality of barbs positioned along the circumference of theannular band between the first plurality of wings and the secondplurality of wings, wherein each of the barbs of the second plurality ofbarbs extend from the annular band, wherein two adjacent barbs, one fromthe first plurality of barbs and the other from the second plurality ofbarbs are aligned along the longitudinal axis; wherein the first andsecond plurality of wings are configured to extend along thelongitudinal axis to provide stability to the device when implantedwithin a blood vessel.
 21. The device of claim 20, wherein the device ismade of shape memory material.
 22. The device of claim 20, wherein adimension of the device defined from the proximal most end to the distalmost end along the longitudinal axis is less than a diameter of theannular band.
 23. The device of claim 20, wherein one apex of theproximal apexes of the first plurality of wings and one apex of thedistal apexes of the second plurality of wings form a pair of adjacentmost opposing apexes, and wherein these opposing apexes are offset alongthe longitudinal axis.
 24. The device of claim 20, wherein said barbsare formed with conduits for enabling plaque treatment material to beconducted to the surface of the barbs through capillary channels. 25.The device of claim 20, wherein at least one of the first strut and thesecond strut of each wing of the first plurality of wings or at leastone of the third strut and the fourth strut of each wing of the secondplurality of wings is directly connected to one of the plurality ofbarbs.
 26. An intravascular device comprising: an annular band defininga longitudinal axis between proximal and distal ends of the device andhaving: a first plurality of wings along a first side of the annularband, each wing of the first plurality of wings having first and secondstruts forming a proximal apex and extending longitudinally such thatthe proximal apexes of the first plurality of wings form the proximalmost end of the device; a second plurality of wings along a second sideof the annular band, the first side of the annular band spaced from thesecond side along the longitudinal axis, each wing of the secondplurality of wings having third and fourth struts forming a distal apexand extending longitudinally such that the distal apexes of the secondplurality of wings form the distal most end of the device; and aplurality of barbs positioned along a circumference of the annular bandbetween the first plurality of wings and the second plurality of wings,wherein each of the barbs of the plurality of barbs extend from theannular band pointed along a single circumferential direction, andwherein said barbs are formed with conduits for enabling plaquetreatment material to be conducted to the surface of the barbs throughcapillary channels; wherein the first and second plurality of wings areconfigured to extend along the longitudinal axis to provide stability tothe device when implanted within a blood vessel.
 27. The device of claim26, wherein the device is made of shape memory material.
 28. The deviceof claim 26, wherein a dimension of the device defined from the proximalmost end to the distal most end along the longitudinal axis is less thana diameter of the annular band.
 29. The device of claim 26, wherein oneapex of the proximal apexes of the first plurality of wings and one apexof the distal apexes of the second plurality of wings form a pair ofadjacent most opposing apexes, and wherein these opposing apexes areoffset along the longitudinal axis.
 30. The device of claim 26, whereinthe plurality of barbs comprises a first plurality of barbs and thedevice further comprises a second plurality of barbs positioned alongthe circumference of the annular band between the first plurality ofwings and the second plurality of wings, wherein each of the barbs ofthe second plurality of barbs extend from the annular band.
 31. Thedevice of claim 30, wherein two adjacent barbs, one from the firstplurality of barbs and the other from the second plurality of barbs arealigned along the longitudinal axis.
 32. The device of claim 26, whereinat least one of the first strut and the second strut of each wing of thefirst plurality of wings or at least one of the third strut and thefourth strut of each wing of the second plurality of wings is directlyconnected to one of the plurality of barbs.
 33. An intravascular devicecomprising: an annular band defining a longitudinal axis betweenproximal and distal ends of the device and having: a first plurality ofwings along a first side of the annular band, each wing of the firstplurality of wings having first and second struts forming a proximalapex and extending longitudinally such that the proximal apexes of thefirst plurality of wings form the proximal most end of the device; asecond plurality of wings along a second side of the annular band, thefirst side of the annular band spaced from the second side along thelongitudinal axis, each wing of the second plurality of wings havingthird and fourth struts forming a distal apex and extendinglongitudinally such that the distal apexes of the second plurality ofwings form the distal most end of the device; and a plurality of barbspositioned along a circumference of the annular band between the firstplurality of wings and the second plurality of wings, wherein each ofthe barbs of the plurality of barbs extend from the annular band pointedalong a single circumferential direction; wherein at least one of thefirst strut and the second strut of each wing of the first plurality ofwings or at least one of the third strut and the fourth strut of eachwing of the second plurality of wings is directly connected to one ofthe plurality of barbs; and wherein the first and second plurality ofwings are configured to extend along the longitudinal axis to providestability to the device when implanted within a blood vessel.
 34. Thedevice of claim 33, wherein the device is made of shape memory material.35. The device of claim 33, wherein a dimension of the device definedfrom the proximal most end to the distal most end along the longitudinalaxis is less than a diameter of the annular band.
 36. The device ofclaim 33, wherein one apex of the proximal apexes of the first pluralityof wings and one apex of the distal apexes of the second plurality ofwings form a pair of adjacent most opposing apexes, and wherein theseopposing apexes are offset along the longitudinal axis.
 37. The deviceof claim 33, wherein the plurality of barbs comprises a first pluralityof barbs and the device further comprises a second plurality of barbspositioned along the circumference of the annular band between the firstplurality of wings and the second plurality of wings, wherein each ofthe barbs of the second plurality of barbs extend from the annular band.38. The device of claim 37, wherein two adjacent barbs, one from thefirst plurality of barbs and the other from the second plurality ofbarbs are aligned along the longitudinal axis.
 39. The device of claim33, wherein said barbs are formed with conduits for enabling plaquetreatment material to be conducted to the surface of the barbs throughcapillary channels.